产右旋糖酐酶埃氏交替单胞菌的筛选、鉴定及酶活分析

Screening,identification and activity analysis of a Dextranase-producing Altermonas espejiana strain

从连云港港口海泥样本筛选到一株产右旋糖酐酶的埃氏交替单胞菌A.espejiana YSN412,对其所产的右旋糖酐酶AesDEX酶学性质进行了分析,对其产酶条件进行了摸索。AesDEX最适反应温度为30℃,最适pH值为8。在30℃下保温2.5h,残余相对酶活在95%以上,而在50℃下保温2.5h后只有14%的残余酶活力。该菌株产酶培养的最佳碳源和氮源,分别是纤维二糖和酵母粉,最适产酶培养温度为30℃,NaCl浓度为2%,初始pH为8时培养液酶活力最高。该菌株培养12h时培养液酶活力达到最高值9U/mL。本实验筛选到的A.espejiana YSN412菌株产酶较为迅速,所产的右旋糖酐酶AesDEX酶活最适温度较低,在工业生产上具有潜在降低成本、提高生产效率的优势。

A dextranase producing strain Altermonas espejiana YSN412 was isolated from a beach mud sample of Lianyungang port. The enzymatic properties of the dextranase AesDEX were analyzed. The culture condition for production of enzyme from the strain was investigated. The optimum temperature and pH value of the enzyme were 30℃ and 8 respectively. After incubation at 30℃ and 50℃ for 2.5h,the remnant relative enzymatic activities were 95% and 14% respectively. The optimum carbon and nitrogen sources were cellobiose and yeast powder respectively. When the concentration of NaCl was 2% （w/w） and the initial pH value was 8,the enzymatic activity of the liquid culture reached its maximum 9U/mL after culturing the strain for 12h. The A. espejiana YSN412 strain isolated and identified in this study produced dextranase quickly and the dextranase AesDEX had a low optimum temperature for enzymatic activity. The enzyme showed the potential to lower the cost and increase the efficiency in industry.